Polycrystalline TiO2 particles synthesized via one-step rapid heating method as electrons transfer intermediate for Rhodamine B removal

In this work, a one-step rapid heating method for the synthesis of polycrystalline TiO2 particles was demonstrated. By rapid and direct transfer of heat into the precursor solution, coupled with proper control of heating duration; polycrystalline TiO2 particles have been successfully synthesized in 45 min. TEM and XRD analyses demonstrated the polycrystalline nature of the TiO2 particles synthesized at 45 min composes of a mixture of 74% anatase phase (29.40 nm) and 26% brookite phase (21.07 nm). These polycrystalline TiO2 particles degraded 80% of Rhodamine B (RhB) after 60 min of visible light irradiation. The self-sensitization of RhB and crystal defects in polycrystalline TiO2 particles (electron donors), had produced more electrons in the conduction band of TiO2. These electrons then reduced the oxygen molecules to center dot O-2(-) free radicals. Both electrons and center dot O-2(-) free radicals were the main reactive species that degraded the RhB molecules as verified by scavenger tests. The promising photocatalytic performance together with the simple and low cost synthesis method, have provided a feasible alternative in the development of visible light active photocatalyst for organic dye removal.

Automated summary

A one-step rapid heating method for the synthesis of polycrystalline TiO2 particles was demonstrated in this study, which exhibited promising photocatalytic performance in degrading organic dyes under visible light irradiation. The synthesized TiO2 particles were found to be a mixture of anatase and brookite phases, with crystal defects and self-sensitization of RhB contributing to enhanced electron production for degradation of RhB molecules.